Conventional methods for measuring the stiffness of an internal organ, such as the liver, using an MRI apparatus include an imaging method called MR elastography. In MR elastography, a vibrator is placed between a receiving coil of an MRI apparatus and a subject, and the vibrator vibrates an internal organ of the subject, whereby an MR image in which coefficients of elasticity indicating the stiffness can be obtained. In general, a region of fibrosis in an internal organ is specified in such MR elastography, and the specified region is subjected to biopsy.